Broken and cracked eggshells cause major economic losses to the egg production industry. An F2 population of 262 hens obtained by crossing a strong egg shell line with a weak egg shell line of the White Leghorn breed ...Broken and cracked eggshells cause major economic losses to the egg production industry. An F2 population of 262 hens obtained by crossing a strong egg shell line with a weak egg shell line of the White Leghorn breed was used for detecting the quantitative trait loci （QTL） affecting eggshell quality. The 2 lines were developed from the same founder population by two-way selection for egg shell strength with nondestructive deformation. Of the 1 014 microsatellite markers tested, 35 were mapped on 10 autosomal linkage groups. There was no informative marker on chromosome Z. The QTLs associated with 7 traits, i.e., body weight, short length of egg, long length of egg, eggshell strength, eggshell thickness （EST）, eggshell weight （ESW）, and egg weight （EW）, were identified. Highly significant （P〈0.01） QTLs associated with EST and ESW and a significant （P〈 0.05） QTL associated with EW were mapped to a region flanking ABR0545 and ABR0362 on chromosome 9. These QTLs are good candidates to be employed in the development of strategies for reducing the number of broken and cracked eggs in commercial layer houses by employing marker assisted selection.展开更多
In this study, 21 microsatellite markers were used to genotype 196 Egyptian local chickens obtained from Fayoumi (n = 35), Dandarawy (n = 30), Baladi (n = 29), Sinai (n = 30), El-Salam (n = 36), and Golden Montazah (n...In this study, 21 microsatellite markers were used to genotype 196 Egyptian local chickens obtained from Fayoumi (n = 35), Dandarawy (n = 30), Baladi (n = 29), Sinai (n = 30), El-Salam (n = 36), and Golden Montazah (n = 36) strains. The results were compared to two pure commercial chicken populations reared in Japan-White Leghorn (n = 42) and Rhode Island Red (n = 43). A total of 162 alleles were observed, with an average of 7.7 alleles per locus. The average expected heterozygosity for the Egyptian chickens was 0.595. The closest pairwise Nei’s genetic distance was recorded between Sinai and Golden Montazah (0.038) and the smallest pairwise FST value (0.006) was observed between Baladi and Sinai. The most probable structure clustering of the eight studied populations was at K = 6. Baladi, Sinai and Golden Montazah strains were clustered together forming admixed mosaic cluster. Dandarawy ranked firstly and contributed the most to aggregate genetic diversity based on two prioritization methods. The information resulting from this study may be used as an initial guide to design further investigations for development of sustainable genetic improvement and conservation programs for the Egyptian chicken genetic resources.展开更多
文摘Broken and cracked eggshells cause major economic losses to the egg production industry. An F2 population of 262 hens obtained by crossing a strong egg shell line with a weak egg shell line of the White Leghorn breed was used for detecting the quantitative trait loci （QTL） affecting eggshell quality. The 2 lines were developed from the same founder population by two-way selection for egg shell strength with nondestructive deformation. Of the 1 014 microsatellite markers tested, 35 were mapped on 10 autosomal linkage groups. There was no informative marker on chromosome Z. The QTLs associated with 7 traits, i.e., body weight, short length of egg, long length of egg, eggshell strength, eggshell thickness （EST）, eggshell weight （ESW）, and egg weight （EW）, were identified. Highly significant （P〈0.01） QTLs associated with EST and ESW and a significant （P〈 0.05） QTL associated with EW were mapped to a region flanking ABR0545 and ABR0362 on chromosome 9. These QTLs are good candidates to be employed in the development of strategies for reducing the number of broken and cracked eggs in commercial layer houses by employing marker assisted selection.
文摘In this study, 21 microsatellite markers were used to genotype 196 Egyptian local chickens obtained from Fayoumi (n = 35), Dandarawy (n = 30), Baladi (n = 29), Sinai (n = 30), El-Salam (n = 36), and Golden Montazah (n = 36) strains. The results were compared to two pure commercial chicken populations reared in Japan-White Leghorn (n = 42) and Rhode Island Red (n = 43). A total of 162 alleles were observed, with an average of 7.7 alleles per locus. The average expected heterozygosity for the Egyptian chickens was 0.595. The closest pairwise Nei’s genetic distance was recorded between Sinai and Golden Montazah (0.038) and the smallest pairwise FST value (0.006) was observed between Baladi and Sinai. The most probable structure clustering of the eight studied populations was at K = 6. Baladi, Sinai and Golden Montazah strains were clustered together forming admixed mosaic cluster. Dandarawy ranked firstly and contributed the most to aggregate genetic diversity based on two prioritization methods. The information resulting from this study may be used as an initial guide to design further investigations for development of sustainable genetic improvement and conservation programs for the Egyptian chicken genetic resources.
